University of Illinois Chicago
Host: Dr. Winter
Abstract: Luminescence Upconversion (UC) is a non-linear photophysical process that allows to generate high-energy photons from low-energy radiations. Generally, light-harvesting sensitizers/donors are employed to transfer excited-triplet energy to acceptor molecules (with appreciable emission quantum). It’s widely known that the donor-to-acceptor energy transfer might be affected/altered by various parameters such as ground state molecular oxygen, non-ideal donor-acceptor interactions, or/and radiationless deactivation of the excited-state molecules. To remediate the quenching/deactivation process and improve the quantum efficiency of the UC process, we have designed several donor-acceptor dyads with tunable spin state(s). In this work, we aim to ascertain that i) donor-acceptor interactions can be modulated (through-bond vs. through-space) and ii) the underlying UC photophysical processes cannot be impacted by molecular oxygen if the overall spin state of the dyad does not match with ground state oxygen. My presentation will highlight the synthesis and photophysical characterization of several donor-acceptor bichromophores or dyads, which we employed for UC investigations.
Bio: Jean-Luc Ayitou is presently an Assistant Professor of Chemistry at UIC; he joined UIC in 2021 after being a faculty member in the Chemistry Department at Illinois Tech (2016-2021). Jean-Luc earned his B.Sc. (in 2008) and Ph.D. (in 2013) degrees, as a joint NSF and Merck Lab graduate Fellow, from North Dakota State University (NDSU) under the guidance of Professor Sivaguru Jayaraman. At NDSU, Jean-Luc’s graduate research work focused on asymmetric photochemistry, working on the photochemistry of axially chiral acrylanilides and oxoamides. Jean-Luc then continued his research training as a UNCF-Merck Postdoctoral Fellow and University of California President’s Postdoctoral Fellow from June 2013 to July 2016 under the mentorship of Professor Miguel Garcia-Garibay at UCLA, where he worked on mechanistic solid-state photochemistry and molecular rotors. Since August 2016, as an independent investigator, Jean-Luc and his students have been working on novel purely organic chromophores and their corresponding donor-acceptors dyads. His research also covers the areas of energy upconversion and organic polymeric materials. Jean-Luc is the recipient of the NSF Early CAREER Award (2018) and the 2021 NOBCChE Young Scientist Award. In addition, he has also been recognized as a “2020 Researcher to Know” by the Illinois Science & Technology Coalition.